The newly-discovered A. leptosome has a slender body, distinct
sensory cavities on the head, a sheath that covers part of the
dorsal fin and a unique color pattern.

Four species of arapaima were recognized by scientists in the
1800s, but were lumped into one by British scientist Albert
Günther in 1848 — a prevailing wisdom that had largely gone
unchallenged until recently.

Dr. Donald Stewart of the SUNY College of Environmental Science
and Forestry in Syracuse, N.Y., has shown that there are actually
five species of the giant
fish, and made the most recent discovery.

"Until this year, no taxonomist has questioned Günther's opinion
about these iconic fishes," he wrote in his findings.

Identifying and understanding all of the arapaima's different
features will aid in the health of the fish, the conservation of
river ecology and the balance of nature, according to Stewart.

"There is a growing aquaculture industry for arapaima, so they
are being moved about and stocked in ponds for rearing," he said. "Eventually,
pond-reared fishes escape and, once freed, the ecological effects
are irreversible. A species that is endangered in its native
habitat may become an invasive species in another habitat.

"The bottom line is that we shouldn't be moving these large,
predatory fishes around until the species and their natural
distributions are better known. Given the uncertainties,
precaution is needed."